便于复习

注1：% * / 的优先级高于 + -

注2：强制类型转换需要在变量上加括号例如：(int)(n % 10);

import java.util.*;
class Main{
    static class F{
        int s0, s1, s2;
        public F(int a, int b, int c){
            s0 = a;
            s1 = b;
            s2 = c;
        }
    }

    private static int N = 19, P = (int) 1e9 + 7;
    private static F[][][][] f;
    private static long[] power10;
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int t = sc.nextInt();
        init();
        while(t-- > 0){
            long l = sc.nextLong();
            long r = sc.nextLong();
            System.out.println(mod(dp(r) - dp(l-1), P));
        }
    }

    private static int mod(long x, int y){
        return (int) (x % y + y) % y;
    }

    private static void init(){
        power10 = new long[N];
        power10[0] = 1;
        for(int i = 1; i < N; i++) power10[i] = power10[i-1] * 10;

        f = new F[N][10][7][7];
        for(int i = 0; i < N; i++){
            for(int j = 0; j <= 9; j++){
                for(int a = 0; a < 7; a++){
                    for(int b = 0; b < 7; b++){
                        f[i][j][a][b] = new F(0, 0, 0);
                    }
                }
            }
        }
        for(int j = 0; j <= 9; j++){
            if(j == 7) continue;
            F v = f[1][j][j % 7][j % 7];
            v.s0 += 1;
            v.s1 += j;
            v.s2 += j * j;
            //f[1][j][j % 7][j % 7] = v;                !!!可以注释掉
        }
        for(int i = 2; i < N; i++){
            for(int j = 0; j <= 9; j++){
                if(j == 7) continue;
                for(int a = 0; a < 7; a++){
                    for(int b = 0; b < 7; b++){
                        for(int k = 0; k <= 9; k++){
                            if(k == 7) continue;
                            F v1 = f[i][j][a][b];
                            F v2 = f[i - 1][k][mod(a - j * (power10[i - 1] % 7), 7)][mod(b - j, 7)];
                            v1.s0 = mod(v1.s0 + v2.s0, P);
                            v1.s1 = mod(v1.s1
                                    + j * (power10[i-1] % P) % P * v2.s0
                                    + v2.s1, P);
                            v1.s2 = mod(v1.s2 
                                    + j * j * (power10[i-1] % P) % P * (power10[i-1] % P) % P * v2.s0
                                    + 2 * j * (power10[i-1] % P) % P * v2.s1
                                    + v2.s2, P);
                            //f[i][j][a][b] = v1;       !!! 可以注释掉
                        }
                    }
                }
            }
        }
    }

    private static F get(int i, int j, int a, int b){
        int s0 = 0, s1 = 0, s2 = 0;
        for(int x = 0; x < 7; x++){
            for(int y = 0; y < 7; y++){
                if(x != a && y != b){
                    F v = f[i][j][x][y];
                    s0 = (s0 + v.s0) % P;
                    s1 = (s1 + v.s1) % P;
                    s2 = (s2 + v.s2) % P;
                }
            }
        }
        return new F(s0, s1, s2);
    }

    private static int dp(long n){
        if(n == 0) return 0;
        long backup_n = n % P;
        List<Integer> nums = new ArrayList<>();
        while(n > 0){
            nums.add((int) (n % 10));
            n /= 10;
        }
        int res = 0;
        long last_a = 0, last_b = 0;
        for(int i = nums.size()-1; i >= 0; i--){
            int x = nums.get(i);
            for(int j = 0; j < x; j++){
                if(j == 7) continue;
                int a = mod(-last_a * (power10[i + 1] % 7), 7);
                int b = mod(-last_b, 7);
                F v = get(i + 1, j, a, b);
                res = mod(res
                        + (last_a % P) * (last_a % P) % P * (power10[i+1] % P) % P * (power10[i+1] % P) % P * v.s0
                        + 2 * (last_a % P) * (power10[i+1] % P) % P * v.s1
                        + v.s2, P);
            }
            if(x == 7) break;
            last_a = last_a * 10 + x;
            last_b = last_b + x;
            if(i == 0 && last_a % 7 != 0 && last_b % 7 != 0){
                res = mod(res + backup_n * backup_n % P, P);
            }
        }
        return res;
    }
}